The present invention relates to a novel human gene encoding a polypeptide which is a member of the interleukin (IL)-17 receptor family. More specifically, isolated nucleic acid molecules are provided encoding a human polypeptide named Interleukin 17-Receptor-Like Protein, hereinafter referred to as IL17RLP. IL17RLP polypeptides are also provided, as are vectors, host cells and recombinant methods for producing the same. Also provided are diagnostic methods for detecting disorders related to the immune system and therapeutic methods for treating such disorders. The invention further relates to screening methods for identifying agonists and antagonists of IL17RLP activity.
Cytokines typically exert their respective biochemical and physiological effects by binding to specific receptor molecules. Receptor binding will then stimulate specific signal transduction pathways (Kishimoto, T., et al., Cell 76:253-262 (1994). The specific interactions of cytokines with their receptors are often the primary regulators of a wide variety of cellular process including activation, proliferation, and differentiation (Arai, K.-I, et al., Ann. Rev. Biochem. 59:783-836 (1990); Paul, W. and Seder, R., Cell 76:241-251 (1994)).
Human interleukin (IL)-17 was only recently identified. IL-17 is a 155 amino acid polypeptide which was molecularly cloned from a CD4+ T-cell cDNA library (Yao, Z., et al., J. Immunol. 155:5483-5486 (1995)). The IL-17 polypeptide contains an N-terminal signal peptide and contains approximately 72% identity at the amino acid level with a T-cell trophic herpesvirus saimiri (HVS) gene designated HVS13. High levels of IL-17 are secreted from CD4-positive primary peripheral blood leukocytes (PBL) upon stimulation (Yao, Z., et al., Immunity 3:811-821 (1995)). Treatment of fibroblasts with IL-17, HVS 13, or another murine homologue, designated CTLA8, activate signal transduction pathways and result in the stimulation of the NF-xcexaB transcription factor family, the secretion of IL-6, and the costimulation of T-cell proliferation (Yao, Z., et al., Immunity 3:811-821 (1995)).
An HVS13-Fc fusion protein was used to isolate a murine IL-17 receptor molecule which does not appear to belong to any of the previously described cytokine receptor families (Yao, Z., et al., Immunity 3:811-821 (1995)). The murine IL-17 receptor (mIL-17R) is predicted to encode a type I transmembrane protein of 864 amino acids with an apparent molecular mass of 97.8 kDa. mIL-17R is predicted to possess an N-terminal signal peptide with a cleavage site between alanine-31 and serine-32. The molecule also contains a 291 amino acid extracellular domain, a 21 amino acid transmembrane domain, and a 521 amino acid cytoplasmic tail. A soluble recombinant IL- 17R molecule consisting of 323 amino acids of the extracellular domain of IL-17R fused to the Fc portion of human IgGl was able to significantly inhibit IL-17-induced IL-6 production by murine NIH-3T3 cells (supra).
Interestingly, the expression of the IL-17 gene is highly restricted. It is typically observed primarily in activated T-lymphocyte memory cells (Broxmeyer, H. J. Exp. Med. 183:2411-2415 (1996); Fossiez, F., et al., J. Exp. Med. 183:2593-2603 (1996)). Conversely, the IL-17 receptor appears to be expressed in a large number of cells and tissues including (Rouvier, E., et al., J. Immunol. 150:5445-5456 (1993); Yao, Z., et al., J. Immunol. 155:5483-5486 (1995)). It remains to be seen, however, if IL-17 itself can play an autocrine role in the expression of IL-17. IL-17 has been implicated as a causitive agent in the expression of IL-6, IL-8, G-CSF, Prostaglandin E (PGE2), and intracellular adhesion molecule (ICAM)-1 (Fossiez, F., supra; Yao, Z., et al., Immunity 3:811-821 (1995)). Each of these molecules possesses highly relevent and potentially therapeutically valuable properties. For instance, IL-6 is involved in the regulation of hematopoietic stem and progenitor cell growth and expansion (Ikebuchi, K., et al., Proc. Natl. Acad. Sci. USA 84:9035-9039 (1987); Gentile, P. and Broxmeyer, H. E. Ann. N.Y Acad. Sci. USA 628:74-83 (1991)). IL-8 exhibits a myelosuppressive activity for stem and immature subsets of myeloid progenitors (Broxmeyer, H. E., et al., Ann. Hematol. 71:235-246 (1995); Daly, T. J., et al., J. Biol. Chem. 270:23282-23292 (1995)). G-CSF acts early and late to activate and stimulate hematopoiesis in general (more specifically, neutrophil hematopoiesis) while PGE2 enhances erythropoiesis, suppresses lymphopoiesis and myelopoiesis in general, and strongly suppresses monocytopoiesis (Broxmeyer, H. E. Amer. J Ped. Hematol./Oncol. 14:22-30 (1992); Broxmeyer, H. E. and Williams, D. E. CRC Crit. Rev. Oncol./Hematol. 8:173-226 (1988)).
IL-17 receptor appears to be structurally unrelated to any previously described cytokine receptor family. Despite the existence of 12 cysteine residues in the extracellular domain, their relative positions are not characteristic of receptor molecules classified as members of the immunoglobulin superfamily (Williams, A. and Barclay, A. Annu. Rev. Immunol. 6:381-405 (1988)), the TNFR family (Smith, C., et al., Science 248:1019-1023 (1990)), the hematopoietin receptor family (Cosman, D. Cytokine 5:95-106 (1993)), or any previously described tyrosine kinase receptors (Hanks, S., et al., Science 241:42-52 (1988)).
Thus, there is a need for polypeptides that function as receptor molecules for cytokines and, thereby, function in the transfer of an extracellular signal ultimately to the nucleus of the cell, since disturbances of such regulation may be involved in disorders relating to cellular activation, hemostasis, angiogenesis, tumor metastasis, cellular migration and ovulation, as well as neurogenesis. Therefore, there is a need for identification and characterization of such human polypeptides which can play a role in detecting, preventing, ameliorating or correcting such disorders.
The present invention provides isolated nucleic acid molecules comprising a polynucleotide encoding at least a portion of the IL17RLP polypeptide having the complete amino acid sequence shown in SEQ ID NO:2 or the complete amino acid sequence encoded by the cDNA clone deposited as plasmid DNA as ATCC Deposit Number 209198 on Aug. 8, 1997. The nucleotide sequence determined by sequencing the deposited IL17RLP clone, which is shown in FIGS. 1A, 1B, and 1C (SEQ ID NO:1), contains an open reading frame encoding a complete polypeptide of 426 amino acid residues, including an initiation codon encoding an N-terminal methionine at nucleotide positions 10-12, and a predicted molecular weight of about 47.1 kDa. Nucleic acid molecules of the invention include those encoding the complete amino acid sequence excepting the N-terminal methionine shown in SEQ ID NO:2, or the complete amino acid sequence excepting the N-terminal methionine encoded by the cDNA clone in ATCC Deposit Number 209198, which molecules also can encode additional amino acids fused to the N-terminus of the IL17RLP amino acid sequence.
The encoded polypeptide has a predicted leader sequence of 19 amino acids underlined in FIGS. 1A, 1B, and 1C; and the amino acid sequence of the predicted mature IL17RLP protein is also shown in FIGS. 1A, 1B, and 1C as amino acid residues 20-426, and as residues 1-407 in SEQ ID NO:2.
Thus, one aspect of the invention provides an isolated nucleic acid molecule comprising a polynucleotide comprising a nucleotide sequence selected from the group consisting of: (a) a nucleotide sequence encoding the IL 17RLP polypeptide having the complete amino acid sequence in SEQ ID NO:2 (i.e., positions xe2x88x9219 to 407 of SEQ ID NO:2); (b) a nucleotide sequence encoding the IL17RLP polypeptide having the complete amino acid sequence in SEQ ID NO:2 excepting the N-terminal methionine (i.e., positions xe2x88x9218 to 407 of SEQ ID NO:2); (c) a nucleotide sequence encoding the predicted mature IL17RLP polypeptide having the amino acid sequence at positions 1 to 407 in SEQ ID NO:2; (d) a nucleotide sequence encoding a polypeptide comprising the predicted extracellular domain of the IL17RLP polypeptide having the amino acid sequence at positions 1 to 271 in SEQ ID NO:2; (e) a nucleotide sequence encoding a soluble IL17RLP polypeptide having the predicted extracellular and intracellular domains, but lacking the predicted transmembrane domain; (f) a nucleotide sequence encoding the IL17RLP polypeptide having the complete amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 209198; (g) a nucleotide sequence encoding the IL17RLP polypeptide having the complete amino acid sequence excepting the N-terminal methionine encoded by the cDNA clone contained in ATCC Deposit No. 209198; (h) a nucleotide sequence encoding the mature IL17RLP polypeptide having the amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 209198; (i) a nucleotide sequence encoding the extracellular domain of the IL17RLP polypeptide having the amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 209198; and (j) a nucleotide sequence complementary to any of the nucleotide sequences in (a), (b), (c), (d), (e), (f), (g), (h) or (i) above.
Further embodiments of the invention include isolated nucleic acid molecules that comprise a polynucleotide having a nucleotide sequence at least 90% identical, and more preferably at least 95%, 96%, 97%, 98% or 99% identical, to any of the nucleotide sequences in (a), (b), (c), (d), (e), (f), (g), (h) or (i), above, or a polynucleotide which hybridizes under stringent hybridization conditions to a polynucleotide in (a), (b), (c), (d), (e), (f), (g), (h) or (i), above. This polynucleotide which hybridizes does not hybridize under stringent hybridization conditions to a polynucleotide having a nucleotide sequence consisting of only A residues or of only T residues. An additional nucleic acid embodiment of the invention relates to an isolated nucleic acid molecule comprising a polynucleotide which encodes the amino acid sequence of an epitope-bearing portion of a IL17RLP polypeptide having an amino acid sequence in (a), (b), (c), (d), (e), (f), (g) or (h), above.
An additional nucleic acid embodiment of the invention relates to an isolated nucleic acid molecule comprising a polynucleotide which encodes the amino acid sequence of an epitope-bearing portion of a IL17RLP polypeptide having an amino acid sequence in (a), (b), (c), (d), (e), (f) or (g), above. A further embodiment of the invention relates to an isolated nucleic acid molecule comprising a polynucleotide which encodes the amino acid sequence of a IL17RLP polypeptide having an amino acid sequence which contains at least one amino acid substitution, but not more than 50 amino acid substitutions, even more preferably, not more than 40 amino acid substitutions, still more preferably, not more than 30 amino acid substitutions, and still even more preferably, not more than 20 amino acid substitutions. Of course, in order of ever-increasing preference, it is highly preferable for a polynucleotide which encodes the amino acid sequence of a IL17RLP polypeptide to have an amino acid sequence which contains not more than 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 amino acid substitutions. Conservative substitutions are preferable.
The present invention also relates to recombinant vectors, which include the isolated nucleic acid molecules of the present invention, and to host cells containing the recombinant vectors, as well as to methods of making such vectors and host cells and for using them for production of IL17RLP polypeptides or peptides by recombinant techniques.
In accordance with a further aspect of the present invention, there is provided a process for producing such polypeptide by recombinant techniques comprising culturing recombinant prokaryotic and/or eukaryotic host cells, containing an IL17RLP nucleic acid sequence, under conditions promoting expression of said protein and subsequent recovery of said protein.
The invention further provides an isolated IL17RLP polypeptide comprising an amino acid sequence selected from the group consisting of: (a) the amino acid sequence of the full-length IL17RLP polypeptide having the complete amino acid sequence shown in SEQ ID NO:2 (i.e., positions xe2x88x9219 to 407 of SEQ ID NO:2); (b) the amino acid sequence of the full-length IL17RLP polypeptide having the complete amino acid sequence shown in SEQ ID NO:2 excepting the N-terminal methionine (i.e., positions xe2x88x9218 to 407 of SEQ ID NO:2); (c) the amino acid sequence of the mature IL17RLP polypeptide having the complete amino acid sequence shown in SEQ ID NO:2 (i.e., positions 1 to 407 of SEQ ID NO:2); (d) the amino acid sequence of the predicted extracellular domain of the IL17RLP polypeptide having the complete amino acid sequence shown in SEQ ID NO:2 (i.e., positions 1 to 271 of SEQ ID NO:2); (e) the amino acid sequence of a soluble IL17RLP polypeptide having the predicted extracellular and intracellular domains, but lacking the predicted transmembrane domain; (f) the complete amino acid sequence encoded by the cDNA clone contained in the ATCC Deposit No. 209198; (g) the complete amino acid sequence excepting the N-terminal methionine encoded by the cDNA clone contained in the ATCC Deposit No. 209198; (h) the complete amino acid sequence of the mature IL17RLP encoded by the cDNA clone contained in the ATCC Deposit No. 209198, and; (i) the complete amino acid sequence of the extracellular domain of the IL17RLP encoded by the cDNA clone contained in the ATCC Deposit No. 209198. The polypeptides of the present invention also include polypeptides having an amino acid sequence at least 80% identical, more preferably at least 90% identical, and still more preferably 95%, 96%, 97%, 98% or 99% identical to those described in (a), (b), (c), (d), (e), (f), (g), (h) or (i) above, as well as polypeptides having an amino acid sequence with at least 90% similarity, and more preferably at least 95% similarity, to those above.
An additional embodiment of this aspect of the invention relates to a peptide or polypeptide which comprises the amino acid sequence of an epitope-bearing portion of a IL17RLP polypeptide having an amino acid sequence described in (a), (b), (c), (d), (e), (f), (g), (h) or (i), above. Peptides or polypeptides having the amino acid sequence of an epitope-bearing portion of an IL17RLP polypeptide of the invention include portions of such polypeptides with at least six or seven, preferably at least nine, and more preferably at least about 30 amino acids to about 50 amino acids, although epitope-bearing polypeptides of any length up to and including the entire amino acid sequence of a polypeptide of the invention described above also are included in the invention.
A further embodiment of the invention relates to a polypeptide which comprises the amino acid sequence of an IL17RLP polypeptide having an amino acid sequence which contains at least one amino acid substitution, but not more than 50 amino acid substitutions, even more preferably, not more than 40 amino acid substitutions, still more preferably, not more than 30 amino acid substitutions, and still even more preferably, not more than 20 amino acid substitutions. Of course, in order of ever-increasing preference, it is highly preferable for a peptide or polypeptide to have an amino acid sequence which comprises the amino acid sequence of an IL17RLP polypeptide, which contains at least one, but not more than 20, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 amino acid substitutions. In specific embodiments, the number of additions, substitutions, and/or deletions in the amino acid sequence of FIGS. 1A, 1B, and 1C, or fragments thereof (e.g., the mature form and/or other fragments described herein), is 1-5, 5-10, 5-25, 5-50, 10-50, 50-150, 50-200 or 100-250, conservative amino acid substitutions are preferable.
In another embodiment, the invention provides an isolated antibody that binds specifically to a IL17RLP polypeptide having an amino acid sequence described in (a), (b), (c), (d), (e), (f), (g), (h) or (i) above. The invention further provides methods for isolating antibodies that bind specifically to a IL17RLP polypeptide having an amino acid sequence as described herein. Such antibodies are useful diagnostically or therapeutically as described below.
The invention also provides for pharmaceutical compositions comprising IL17RLP polypeptides, particularly human IL17RLP polypeptides, which may be employed, for instance, to treat disorders relating to cellular activation, hemostasis, angiogenesis, tumor metastasis, cellular migration and ovulation, as well as neurogenesis. Methods of treating individuals in need of IL17RLP polypeptides are also provided.
The invention further provides compositions comprising an IL17RLP polynucleotide or an IL17RLP polypeptide for administration to cells in vitro, to cells ex vivo and to cells in vivo, or to a multicellular organism. In certain particularly preferred embodiments of this aspect of the invention, the compositions comprise an IL17RLP polynucleotide for expression of an IL17RLP polypeptide in a host organism for treatment of disease. Particularly preferred in this regard is expression in a human patient for treatment of a dysfunction associated with aberrant endogenous activity of an IL17RLP polypeptide.
The present invention also provides a screening method for identifying compounds capable of enhancing or inhibiting a biological activity of the IL17RLP polypeptide, which involves contacting a ligand which is inhibited by the IL17RLP polypeptide with the candidate compound in the presence of an IL17RLP polypeptide, assaying receptor-binding activity of the ligand in the presence of the candidate compound and of IL17RLP polypeptide, and comparing the ligand activity to a standard level of activity, the standard being assayed when contact is made between the ligand itself in the presence of the IL17RLP polypeptide and the absence of the candidate compound In this assay, an increase in ligand activity over the standard indicates that the candidate compound is an agonist of IL17RLP activity and a decrease in ligand activity compared to the standard indicates that the compound is an antagonist of IL17RLP activity.
In another aspect, a screening assay for agonists and antagonists is provided which involves determining the effect a candidate compound has on IL17RLP binding to a ligand. In particular, the method involves contacting the ligand with an IL17RLP polypeptide and a candidate compound and determining whether IL17RLP polypeptide binding to the ligand is increased or decreased due to the presence of the candidate compound. In this assay, an increase in binding of IL17RLP over the standard binding indicates that the candidate compound is an agonist of IL17RLP binding activity and a decrease in IL17RLP binding compared to the standard indicates that the compound is an antagonist of IL17RLP binding activity.
It has been discovered that IL17RLP is expressed not only in adult pulmonary tissue, but also in Crohn""s Disease tissue, kidney pyramid, cortex, and medulla tissues, hippocampus, frontal cortex of the brain from a patient with epilepsy, adrenal gland tumor, striatum depression, osteclastoma, endometrial tumor, and hypothalamus from a patient with Schizophrenia. Therefore, nucleic acids of the invention are useful as hybridization probes for differential identification of the tissue(s) or cell type(s) present in a biological sample. Similarly, polypeptides and antibodies directed to those polypeptides are useful to provide immunological probes for differential identification of the tissue(s) or cell type(s). In addition, for a number of disorders of the above tissues or cells, particularly of the immune system, significantly higher or lower levels of IL17RLP gene expression may be detected in certain tissues (e.g., cancerous and wounded tissues) or bodily fluids (e.g., serum, plasma, urine, synovial fluid or spinal fluid) taken from an individual having such a disorder, relative to a xe2x80x9cstandardxe2x80x9d IL17RLP gene expression level, i.e., the IL17RLP expression level in healthy tissue from an individual not having the immune system disorder. Thus, the invention provides a diagnostic method useful during diagnosis of such a disorder, which involves: (a) assaying IL17RLP gene expression level in cells or body fluid of an individual; (b) comparing the IL17RLP gene expression level with a standard IL17RLP gene expression level, whereby an increase or decrease in the assayed IL17RLP gene expression level compared to the standard expression level is indicative of disorder in the immune system.
An additional aspect of the invention is related to a method for treating an individual in need of an increased level of IL17RLP activity in the body comprising administering to such an individual a composition comprising a therapeutically effective amount of an isolated IL17RLP polypeptide of the invention or an agonist thereof.
A still further aspect of the invention is related to a method for treating an individual in need of a decreased level of IL17RLP activity in the body comprising, administering to such an individual a composition comprising a therapeutically effective amount of an IL17RLP antagonist. Preferred antagonists for use in the present invention are IL17RLP-specific antibodies.